Method of producing soluble polyphosphides from red phosphorous using solution chemistry
A method of producing soluble polyphosphides from red phosphorous using solution chemistry is presented. A reaction between an alkali metal alkoxy compound or alkali metal alkyl thiolate compound, such as potassium ethoxide, and shelf stable red phosphorus generated soluble polyphosphides in a variety of organic solvents with the 31 P NMR spectrum being used to detect the species of polyphosphides produced.
1. A method for producing polyphosphide anions soluble in organic solvents, comprising:
providing red phosphorus or a composition of black phosphorus and red phosphorus wherein the red phosphorus has a grain size of about 1.4 mm to about 0.7 mm;
providing an alkali metal alkoxy compound or alkali metal alkyl thiolate compound suspended in an organic solvent;
wherein the alkali metal is sodium or potassium;
allowing the red phosphorus and alkali metal or alkali metal compound to react, wherein the reaction uses reflux or an in-line packed column method;
where the in-line packed column method comprises:
providing a packing column;
loading the packing column with the red phosphorus or composition of black phosphorus and red phosphorus in an inert environment;
purging the packing column with an inert gas;
setting a pressure regulator on the packing column to at least 1 bar;
heating the packing column to a preselected temperature, where the preselected temperature is at least the boiling point of the alkali metal alkoxy compound or alkali metal alkyl thiolate wherein the temperature of the packing column or a reaction solution does not exceed the critical temperature of the organic solvent;
suspending the alkali metal alkoxy compound or alkali metal alkyl thiolate compound in the organic solvent;
flowing the organic solvent through the packing column;
flowing the alkali metal alkoxy compound or alkali metal alkyl thiolate compound in the organic solvent through the packing column; and
forming a compound containing the alkali metal and polyphosphide anions;
wherein the reflux is performed for about 15 minutes to about 2 hours.
2. The method of claim 1 , wherein the alkali metal alkoxy compound or alkali metal alkyl thiolate compound is potassium ethoxide, potassium methoxide, sodium ethoxide, sodium methoxide, or sodium methyl thiolate.
3. The method of claim 1 , wherein the organic solvent is methyl cyanide, dimethyl sulfoxide, dimethylformamide, or a combination of tetrahydrofuran and dimethoxyethane.
4. The method of claim 3 , wherein the combination of tetrahydrofuran and dimethoxyethane is at a volume to volume ratio of 1:1.
5. The method of claim 1 , wherein the organic solvent is evaporated off the compound containing the alkali metal and polyphosphide anions.
6. The method of claim 5 , further comprising redissolving the compound containing the alkali metal and polyphosphide anions in ethanol.
7. The method of claim 6 , further comprising:
subjecting the compounds containing alkali metal and polyphosphide anions to a cation exchange with (Bu 4 N)Cl in ethanol to produce a cation-polyphosphide material; and
redissolving the cation-polyphosphide material in acetonitrile to form free polyphosphide anions.
8. The method of claim 7 , wherein the free polyphosphide anions are P 5 − , P 16 2− , P 21 3− , or a combination thereof.
9. The method of claim 1 , wherein the packing column is stainless steel, cast aluminum, A10 aluminum, A12 aluminum, stainless steel , aluminum-nickel alloy (50-50), polyimide, polyethylene terephthalate, polyamide-imide, nylon, polyvinyl chloride, polycarbonate, polyphthalamide, polysulfone, maleimide/bismaleimide, polyetheretherketone, polyetherimide, polyimide, polyester, acrylonitrile butadiene styrene, carbon reinforced-polyimide, carbon reinforced-polyethylene terephthalate, carbon reinforced-polyamide-imide, carbon reinforced-nylon, carbon reinforced-polyvinyl chloride, carbon reinforced-polycarbonate, carbon reinforced-polyphthalamide, carbon reinforced-polysulfone, carbon reinforced-maleimide/bismaleimide, carbon reinforced-polyetheretherketone, carbon reinforced-polyetherimide, carbon reinforced-polyimide, carbon reinforced-polyester, carbon reinforced-acrylonitrile butadiene styrene, glass reinforced-polyimide, glass reinforced-polyethylene terephthalate, glass reinforced-polyamide-imide, glass reinforced-nylon, glass reinforced-polyvinyl chloride, glass reinforced-polycarbonate, glass reinforced-polyphthalamide, glass reinforced-polysulfone, glass reinforced-maleimide/bismaleimide, glass reinforced-polyetheretherketone, glass reinforced-polyetherimide, glass reinforced-polyimide, glass reinforced-polyester, or glass reinforced-acrylonitrile butadiene styrene.
10. The method of claim 9 , wherein the packing column is stainless steel and wherein the preselected temperature is at least 80° C.
11. The method of claim 9 , wherein the stainless steel packing column is pressurized to about 8 bar.
12. The method of claim 1 , wherein the packing column has an internal diameter of about 9 mm and a length of about 65 mm.
13. The method of claim 12 , wherein the alkali metal alkoxy compound or alkali metal alkyl thiolate is flowed through the packing column at a rate of about 0.5 mL min −1 .
14. The method of claim 1 , further comprising separating the black phosphorus from the polyphosphide anions.